Disc for centrifuge



Feb. 2, 1965 G. s. VOSES 3,168,289

DISC FOR CENTRIFUGE Filed Aug. 20, 1962 2 Sheets-Sheet 1 INVENTOR 6502055' W528 L ATTORNEYS Feb. 2, 1965 G. s. VOSES 3,168,289

v DISC FOR CENTRIFUGE Filed Aug. 20, 1962 2 Sheets-Sheet 2 i Z '-//dINVENTOR 56006:: S. Vases ATTOR NEYS United States Patent ()fifice3,lh8,289 Patented Feb. 2, 1965 3,168,289 DISC FOR CENTREFUGE George S.Voses, Flushing, N.Y., assignor, by mesne assignments, to The CornellMachine (Zonrpany, Springfield, NJL, a corporation of New Jersey FiledAug. 20, 1962, Ser. No. 217,888 3 Claims. (Cl. 259-3) This inventionrelates to an improved centrifugal disc and in particular relates to animproved centrifuge disc shaped for improved control of thehomogenization of materials such as liquid suspensions impelled upon thespinning disc.

In accordance with a well-known type of centrifuge, a

relatively flat disc is spun at selected speeds with material to behomogenized being impelled upon the center of the disc. The disc isshaped so as to form a film of material over the surface of the disc andextending to the outer periphery thereof, where the material isdelivered to an outlet tube or other collection means. During the flowof the material in film form over the surface of the disc, the particlesare abraded and sheared as the result of friction thereof against thesurface of the disc, and as the result of attrition of one particleagainst the other, with resulting homogenization of the particles in thematerial.

This invention makes use of the principle that the friction exerted uponthe particles of the material depends upon the speed of movement thereofand the angle of the disc surface over which they move.

An important object of the invention is to provide a centrifugal disc ofthe above-described type which can be of reduced size and of greaterefliciency in forming the film and in homogenizing the particles. It isparticularly advantageous to be able to reduce either the diameter andmass of the disc, or the speed of rotation thereof, or both, dependingupon the desired conditions of operation of the centrifuge. This resultsin a centrifuge which is more economical to produce and more eificientin operation. Furthermore, in many instances, with a smaller device andlower speed of operation, it is possible to achieve degrees ofhomogenization previously requiring very large, high speed devices.

In accordance with a preferred embodiment of the invention, thecentrifugal disc has a flat center portion mounted on a hub for rotationat selected speed about an axis, the disc being transverse to said axis.The material to be homogenized can be impelled upon the front face ofsaid center portion of the disc.

In accordance with the invention, the centrifugal disc further comprisesan annular intermediate portion or film-forming portion connecting withthe periphery of the center portion and extending forwardly outwardlytherefrom at a shallow acute angle to the transverse. The disc furthercomprises an annular outer portion connecting with the outer peripheryof the intermediate portion and extending forwardly outwardly therefromat a relatively large acute angle to the transverse. The center andintermediate portions of the disc are adapted to form a film of liquidmaterial applied to the front of the center portion by rotation of thedisc at its selected speed and to sustain this film to the outerperiphery of the outer portion or principal homogenization portion ofthe disc.

The angle of the intermediate portion of the disc is such that thecomponent of centrifugal force on the liquid along the surface of theintermediate portion is much greater than the component of centrifugalforce on the liquid normal to the surface of the intermediate portion.As a result, there is only a small amount of friction and resultingbreakdown of particles in the liquid along the intermediate portion ofthe disc.

On the other hand, the angle of the outer portion is preferably suchthat the component of centrifugal force on the liquid normal to thesurface of the outer portion is greater than the component ofcentrifugal force on the liquid along the surface of the outer portion.This will result in production of high friction and high resultingbreakdown by abrasion or attrition of particles in the liquid at theouter portion of the disc.

The respective angles and diameters of the intermediate and outerportions of the disc, together with the selected speed of rotation, aresuch as to insure delivery of the liquid film to the outer periphery ofthe disc with most of the desired homogenization of the liquid occurringover the surface of the outer portion.

The advantage of this shape of the disc is that most of the breakdown ofthe particles occurs in the region of the disc at which they haveachieved the necessary high speed for effective breakdown. Theintermediate portion of the disc is present to assure the effectiveformation of the film and achievement of the desired high speed thereof,with partial homogenizations. With the relative separation of the filmforming and homogenization functions of the disc into the respectiveintermediate and outer portions or zones thereof, it is possible toachieve the desired homogenization of the particles at a relativelyfavorable combination of speed of rotation and diameter of the disc, ascompared to centrifugal discs previously known.

Other objects and advantages of the invention will become apparent fromthe following description, in conjunction with the annexed drawing, inwhich preferred embodiments of the invention are disclosed.

In the drawing,

FIG. 1 is a perspective view of a centrifuge in accordance with theinvention.

FIG. 2 is a transverse section on line 22 of FIG. 3.

FIG. 3 is a longitudinal section of the centrifuge.

Upon reference to the drawing in detail, it will be noted that certaindetails of the device as a whole are not shown since the overall deviceis substantially conventional, with the main improvement being in thecentrifugal disc.

FIGS. 1 and 2 show a casing 10 adapted to be supported upon the floor,such casing 10 being omitted in FIG. 3. Casing 10 contains the drivemotor and associated parts, vacuum pump, etc., all of these beingconventional. An auxiliary casing 11 is shown as mounted on the front ofcasing 10. This casing 11 is generally cylindrical, with its axisextending longitudinally. In this embodiment, but without limitationthereto, the axis of casing 11 is shown as extending horizontally. Sincethe details of casing 11 are conventional, they are not described indetail. It is sufiicient to state that the rear end of casing 11 issecured by flange 12 and clamps 13 to casing 10 by any suitable means.Casing 11 has a tubular peripheral wall 11a which is closed at the frontby annular plate 14 removably secured thereto by clamping means 15. Asight glass 16 is secured over the center opening of plate 14. A tube 17is connected to the top of casing 11 an dis connected through line 18and pump P or other suitable device (both shown diagrammatically) to theatmosphere so as to exhaust air from casing 11 to maintain a selectedvacuum, as measured by vacuum gauge 19 or other suitable device.

Horizontal shaft 20 extends longitudinally through the rear plate 21 ofcasing 11 and into the rear thereof. Shaft 29 is coaxial with theperipheral wall 11a of casing 11. Shaft 20 extends rearwardly of casing11 into the interior of casing 10 where it is connected to the drivemeans (not shown) so that shaft 20 may be rotated at selected speed.Optionally, but without limitation thereto,

' portion or zone32 and outer or principal homogenization portion orzone 33. Disc also comprises a protective return portion 34 connectingwith the outer periphery of portion 33.

The center portion 31 of disc 30 is circular, fiat, and of approximatelythe same diameter as mounting disc 22.

, Said center portion 31 extends transversely to the longitudinal axisof shaft 20, and the plane of disc 31 is indicated diagrammatically bythe broken line 31a.

The intermediate portion 32 of disc 30 connects with the outer peripheryof center portion 31 and extends forwardly outwardly therefrom at ashallow acute angle to the transverse. This is the angle 32a betweenportion 32 and plane 31a.

The annular outer portion 33 connects with the outer periphery ofintermediate portion 32 and extends forwardly therefrom at a relativelylarge acute angle 33a to the transverse. For convenience, the angle 33aof portion 33 is shown relative to a plane 31b which is parallel toplane 31a and which is taken at the junction 32b between disc portions33 and 32. Angle 33a. preferably exceeds 45 degrees. The outer periphery36a of disc 30 is located slightly inwardly radially of the tubularperipheral wall 11a of casing 11. The disc portion 33 isoptionallycurved slightly inwardly just before the peripheral point 30a so as toaccommodate the discharge tube. The return portion 34 extends inwardlyoutwardly from periphery 30a at an angle 34a to the transverse referenceplane 310 shown diagrammatically at the periphery 30a. The front andinner edge 34b of return'portion 34 defines a central opening and islocatedapproxirnately halfway between the endsof casing 11, thisposition being not critical and being selected so as to accommodate theintake and discharge tubes. a

For intake of liquid, a radial tube 40 is extended through wall 11a byany suitable fitting means41 and ,over the rear of tube 42, as bestshown in FIG. 3. The

material to be homogenized may be fed into tube 40 by any suitable means(not shown), under any desired pressure velocity conditions, in thedirection of arrow 44. The material is discharged or impelled from tube42 onto ,disc center portion 31.. Any conventional delivery means can beprovided.

The material treated upon disk fitl is taken off at periphery 30a bymeans of discharge tube 45. The main portion of discharge tube 45extends radially, by means of any suitable fitting 46, through wallliaof casing 11, forwardly'of disc .30. Outwardly of wall 11, tube .45isoptionally bent forwardly longitudinally at 45a, and connected to anysuitable receptacle (not shown), with the material which has beentreated passing th'rough the discharge tube in the direction of arrow47. 'Tube 45 extends inwardly of edge 34b, and is there bent rearwardlyasshown at 45d, with the free end 452 of the tube beinglocated'adjacentthe periphery 30a. As a result, as ma terial'reaches theperiphery 30a it passes into the mouth or end 45e and then is gentlydirected away from the circumferential through the curved tube portion45d and ultimately through all of the sections of the tube 45.

Disc 30 may be spun or otherwise formed from any suitable metal, such ascarbon steel or stainless steel. As stated above, the portion 31 isfiat. The portion 32 may optionally be frusto conical, and optionallymay be part spherical. However, in view of the shallow or small angle32a, the portion 32 has such a large radius of curvature'as to approachthe flat for practical purposes. The portion 33 may also optionally begenerally frusto conical, although with rounded peripheral portions. Thereturn portion 34 may also be generally frusto conical.

The disc 30 is rotated at selected speed, so that the material impelledupon center portion 31 is formed by the center portion 31 andintermediate portion 32 into a film which is sustained to the periphery30a of intermediate portion 33. The film may form on intermediate POI?tion 33 radially outwardly of its junction with center portion 32. Theangle 32:: of intermediate portion 32 is such that the component ofcentrifugal force on the material along the surface of intermediateportion 32. is much greater than the component of centrifugal force onthe liquid normal to the surface of intermediate portion 32. The resultis to minimize friction and resulting breakdown of particles of thematerial along the surface 32. This is advantageous in that thecentrifugal speed of particles along the surface 32 is ordinarily notsufiicient to provide the liquid along the surface of outer portion 33.The

result is to produce a very high amount of friction upon the particlesalong surface 33, with high resulting breakdown of particles in theliquid. This is advantageous in that the surface 33 is oriented so as toproduce high friction of the particles when they are traveling at aspeed such as to insure a high degree of abrasion and attrition andresulting breakdownv of the, particles. This makes possible maximumfavorable design. factors of the disc .asa whole. The respective anglesand diameters of intermediate and outer. portions 32 and 33 relative tothe selected speed of rotation of'the disc are such as to insure,delivery of the liquid film to the outer periphery 30a of disc 39 with.the principal portion of the desired homogenization of the liquidoccurring over the surface of outer portion 33.

While a preferred embodiment of the invention has been disclosed, andvarious possible changes, omissions and additions have been disclosed,it will be apparent that various other changes, omissions and additionsmay be made in the invention without departing from the scope and spiritthereof.

What is claimed is:

1. In a centrifuge of the type described, a centrifugal discforope'ration at selected speed comprising a flat center portion forrotation at said selected speed'about an axis, said disc beingtransverse to said axis, an vannular intermediate portion connectingwith the outer periph- -ery of ''said center portion and extendingforwardly angle tothe transverse, said center and intermediate portionsbeing adapted to form a film of liquid, material impelled upon the frontof. said center portion by rotation j of said disc at said' selectedspeed and to sustain said film to the outer periphery of said outerportion, the angle of said intermediate portion "being such that thecomponent of centrifugal force on the liquid along the surface of saidintermediate portion is much greater than the component of centrifugalforce on the liquid normal to the surface of said intermediate portionso as to minimize friction and resulting abrasion and attrition ofparticles in said liquid, the angle of said outer portion being suchthat the component of centrifugal force on the liquid normal to thesurface of said outer portion is greater than the component ofcentrifugal force on the liquid along the surface of said outer portionso as to produce high friction and high resulting abrasion and attritionof particles in said liquid, the respective angles and diameters of saidintermediate and outer portions r-lative to said selected speed beingsuch as to ensure delivery of said liquid film to the outer periphery ofsaid disc with the major portion of the desired homogenization of theliquid occurring over the surface of said outer portion, and means fortaking material from said disc positioned to receive said materialbeyond the outer periphery of said outer portion.

2. In a centrifuge of the type described, a centrifugal disc foroperation at selected speed comprising a center portion for rotation atsaid selected speed about an axis, said disc being transverse to saidaxis, an annular intermediate portion connecting with the outerperiphery of said center portion and extending forwardly outwardlytherefrom at a shallow acute angle to the transverse, and an annularouter portion connecting with the outer periphery of said intermediateportion and extending forwardly outwardly therefrom at a large acuteangle to the transverse, said center and intermediate portions beingadapted to form a film of liquid material impelled upon the front ofsaid center portion by rotation of said disc at said selected speed andto sustain said film to the outer periphery of said outer portion, theangle of said intermediate portion being such that the component ofcentrifugal force on the liquid along the surface of said intermediateportion is much greater than the component of centrifugal force on theliquid normal to the surface of said intermediate portion so as tominimize friction and resulting abrasion and attrition of particles insaid liquid, the angle of said outer portion being such that thecomponent of centrifugal force on the liquid normal to the surface ofsaid outer portion is greater than the component of centrifugal force onthe liquid along the surface of said outer portion so as to produce highfriction and high resulting abrasion and attrition of particles in saidliquid, the respective angles and diameters of said intermediate andouter portions relative to said selected speed being such as to ensuredelivery of said liquid film to the outer periphery of said disc withthe major portion of the desired homogenization of the liquid occurringover the surface of said outer portion, and means for taking materialfrom said disc positioned to receive said material beyond the outerperiphery of said outer portion.

3. Centrifugal disc in accordance with claim 2, the angle to thetransverse of said outer portions being greater than degrees.

References Cited in the file of this patent UNITED STATES PATENTS825,732 Janson July 10, 1906 1,363,572 Dalzell Dec. 28, 1920 2,318,293Cornell May 4, 1943 2,612,356 Borck Sept. 30, 1952 2,673,075 Borck Mar.23, 1954 2,785,765 Cornell Mar. 19, 1957 2,952,448 Cornell Sept. 13,1960

1. IN A CENTRIFUGE OF THE TYPE DESCRIBED, A CENTRIFUGAL DISC FOROPERATION AT SELECTED SPEED COMPRISING A FLAT CENTER PORTION FORROTATION AT SAID SELECTED SPEED ABOUT AN AXIS, SAID DISC BEARINGTRANSVERSE TO SAID AXIS, AN ANNULAR INTERMEDIATE PORTION CONNECTING WITHTHE OUTER PERIPHERY OF SAID CENTER PORTION AND EXTENDING FORWARDLYOUTWARDLY THEREFROM AT A SHALLOW ACUTE ANGLE TO THE TRANSVERSE, AND ANANNULAR OUTER PORTION CONNECTING WITH THE OUTER PERIPHERY OF SAIDINTERMEDIATE PORTION AND EXTENDING FORWARDLY OUTWARDLY THEREFROM AT ALARGE ACUTE ANGLE TO THE TRANSVERSE, SAID CENTER AND INTERMEDIATEPORTIONS BEING ADAPTED TO FORM A FILM OF LIQUID MATERIAL IMPELLED UPONTHE FRONT OF SAID CENTER PORTION BY ROTATION OF SAID DISC AT SAIDSELECTED SPEED AND TO SUSTAIN SAID FILM TO THE OUTER PERIPHERY OF SAIDOUTER PORTION, THE ANGLE OF SAID INTERMEDIATE PORTION BEING SUCH THATTHE COMPONENT OF CENTRIFUGAL FORCE ON THE LIQUID ALONG THE SURFACE OFSAID INTERMEDIATE PORTION IS MUCH GREATER THAN THE COMPONENT